BARRIE, Ont. -- The brutal and seemingly never-ending winter of 2014 has already taken a substantial avian toll in parts of central and eastern Canada. With yet another polar vortex poised to strike, the situation looks dire for many species of birds.
Significant mortality in wild turkeys has already been confirmed in parts of central and eastern Canada, with another bout of bitter cold sure to make matters worse.
Cold temperatures and snow depths of more than 25 centimetres for several weeks are potentially fatal for wild turkeys, according to turkey specialist Jim Pack in West Virginia.
Two consecutive polar vortices so far this year, and snow depths exceeding 120 centimetres since early January, have already hit turkeys very hard in parts of Ontario.
According to Josef Hamr and colleagues at Laurentian University, such winters typically result in wild-turkey losses exceeding 60 per cent of the population.
The Wisconsin Department of Natural Resources has confirmed a "heavy toll" in wild turkeys there so far this winter, with more record cold to come.
Meanwhile, veterinarian Bob Denton confirms large die-offs of birds "due to cold weather and lack of food" as far south as Texas.
Migrating birds are especially vulnerable to extreme cold and deep snow. Increasing accounts of dead and starving waterfowl, mainly ducks, have widely surfaced since mid-February.
Researchers explain northbound waterfowl have arrived to wintry conditions and deep snow that has made food largely unavailable. Significant numbers of mallards have been reported in areas of south-central Ontario, where fields are covered with more than 100 centimetres of snow and temperatures of -20 C to -30 C. Dead ducks have been reported in the Georgian Bay and Lake Ontario areas. Others are clumped on lake ice, too weak to fly, their food reserves exhausted.
In some cases, ducks have been reported falling from the sky, picked up exhausted and emaciated.
Researchers suggest northbound ducks in late winter are not genetically programmed to return south if they encounter bad conditions. Instead, they hunker down to await improving conditions, sometimes with fatal consequences.
On Feb. 1, starving Canada geese were reported vainly seeking food in deep snow in Pennsylvania. Similar reports surfaced the next day in Illinois.
At St. Catharines, Ont., the local fire department was dispatched to rescue ducks that had been frozen on the ice in Lake Ontario.
This winter, the Great Lakes are more than 90 per cent frozen over. That has forced tens of thousands of wintering and migrating diving ducks into the few remaining open-water areas, such as the St. Clair River. There, local reports confirm countless dead and dying ducks, the victims of the "icy winter of 2014," according to local observers.
Many of this year's avian victims are red-breasted mergansers, fish-eating diving ducks that have been forced inland in a hopeless effort to find food. What they have encountered is frozen snow-covered landscapes. Many have been found, dead or near-death, in recent days, tens of kilometres from any open water. On Feb. 17, one was photographed near Barrie squatted atop a large snow drift, the nearest open water some 80 kilometres away. The next day, one was spotted standing in a snowy field near Orangeville, Ont.
There are fears that unless the brutal conditions ease soon, the resulting negative impact on the physiological condition of waterfowl in much of eastern North America might impact on 2014 reproductive success.
So far, there are no indications the weather patterns generating the extreme cold are about to change any time soon, according to Environment Canada.
Robert Alison is a freelance writer and zoologist based in Barrie, Ont.